Organic chemistry



United States Patent 3,419,617 ORGANIC CHEMISTRY Richard C. Doss,Bartlesville, Okla, assignor to Phillips Petroleum Company, acorporation of Delaware No Drawing. Continuation-impart of abandonedapplication Ser. No. 399,862, Sept. 28, 1964. This application June 7,1965, Ser. No. 462,136

9 Claims. (Cl. 260-601) ABSTRACT OF THE DISCLOSURE Alpha formyl sulfideor alpha,alpha bis(hydrocarbylthio) aldehyde is formed by reactingalpha-halo aldehyde or alpha,alpha-dihalo aldehyde, respectively, with athiol in the presence of pyridine and derivatives thereof.

This is a continuation-impart of copending US. appli cation Ser. No.399,862 filed Sept. 28, 1964 and now abandoned.

This invention relates to a method of preparing an ocformyl sulfide.This invention also relates to a method of preparing anu,u-bis-(hydrocarbylthio) aldehyde. This invention also relates to(n-butylthio)acetaldehyde and his (n-butylthio)acetaldehyde and themethods of making these compounds.

It has been reported that chloroacetaldehy-de, in pure form or as anaqueous solution, reacts with alkanethiols in the presence of a minoramount of acid to give 1,1,2- tris(alkylthio)ethanes which, upon heatingwith a nonvolatile acid, are converted to l,2-bis(alkylthio)ethylenes.

However, it has been found that the direct replacement of halogen in anu-halo aldehyde or a,u-dihalo aldehyde can be made in a manner such thatthe aldehyde group or groups are left intact, thereby directly yielding,respectively, an a-formyl sulfide or an a,a-bis(hydrocarbylthio)aldehyde. Surprisingly, the reaction can be effected only in thepresence of pyridine and certain derivatives thereof as the solvent. Thedesired reaction does not occur in the presence of solvents such aswater, ether and the like.

Also surprisingly, it has been found that When 1- butanethiol is reactedWith a haloacetaldehyde in the presence of pyridine and certainderivatives thereof as the solvent, the novel compound(n-butylthio)acetaldehyde is formed.

Also surprisingly, it has been found that when l-butanethiol is reactedwith a dihaloacetaldehyde in the presence of pyridine and certainderivatives thereof as the solvent, the novel compound bis(n-butylthio)acetaldehyde is formed.

Accordingly, it is an object of this invention to provide a new andimproved process for preparing an ot-formyl sulfide and anOL,0t-biS(hYdI'OCaIby1thiO) aldehyde. It is also an object of thisinvention to provide novel organic compounds and the method forproducing same.

Other aspects, objects and the several advantages of the invention willbe apparent to those skilled in the art from the description and theappended claims.

In accordance with this invention, an u-formyl sulfide is prepared bythe reaction of an a-halo aldehyde with a thiol or dithiol in a solventcomprising at least one material selected from the group consisting ofpyridine, quinoline, isoquinoline, and a lower alkyl derivative of atleast one of these heterocyclic bases. The reaction can be representedby the equation:

3,419,617. Patented Dec. 31, 1968 Where R is a monovalent hydrocarbonradical selected from the group consisting of alk-yl, cycloalkyl,alkenyl, cycloalkenyl, aryl and combinations thereof, preferably alkyland cycloalkyl; R is at least one member selected from the groupconsisting of R and hydrogen; X is a halogen selected from the groupconsisting of fluorine, chlorine, bromine and iodine, preferablychlorine or bromine; Y is a divalent hydrocarbon radical selected fromthe group consisting of alkylene, cycloalkylene, alkenylene,cycloalkenylene, arylene, and combinations thereof; the number of carbonatoms in R or Y does not exceed 18, i.e., is from 1 to 18; and the totalnumber of carbon atoms in the OL-fOI'IIlYl sulfide does not exceed 30,i.e., is from 3 to 30. All carbon atoms ranges herein are inclusiveunless otherwise specified.

Also in accordance with this invention, anu,u-biS(hydrocarbylthio)aldehyde is prepared by the reaction of anu,u-dihalo aldehyde with a thiol in a solvent comprising at least oneselected from the group consisting of pyridine, quinoline, isoquinoline,and a lower alkyl derivative of at least one of these heterocyclicbases. The reaction can be represented by the equation:

where R is a monovalent hydrocarbon radical selected from the groupconsisting of alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl andcombinations thereof; R is a member selected from the group consistingof R and hydrogen; X is a halogen selected from the group consisting offluorine, chlorine, bromine, and iodine, preferably chlorine or bromine;the number of carbon atoms in R being from 1 to 18; and the total numberof carbon atoms in the ct,ot-bis(hydrocarbylthio)aldehyde being from 4to 40.

As examples illustrative of the reaction as represented by the equationsabove, bromoacetaldehyde reacts with l-propanethiol to yield(n-propylthio)acetaldehyde, 1,4- butanedithiol reacts with2-chloropropionaldehyde to give 1,4-bis l-formylethylthio)butane,dibromoacetaldehyde reacts with ethanethiol to yieldbis(ethylthio)acetaldehyde, and 2,2-dichloropropionaldehyde reacts withl-butanethiol to give 2,2-bis(n-butylthio)propionaldehyde.

Examples of some a-formyl sulfides that can be prepared by the method ofthis invention are ('methylthio acetaldehyde,

(ethylthio) acetaldehyde,

(n-b utylthio acetaldehyde,

(phenylthio acetaldehyde,

(benzylthio) acetaldehyde,

2- (isobutylthio propionaldehyde,

2-n-octyl-2- (n-dodecylthio decanal,

2- (ethylthio eicosanal,

cyclopentyl (n-octadecylthio) acetaldehyde,

2- allylthio -3-phenylpropionaldehyde,

2- (2-cyclohexen-1-yl) -2- (p-tolylthio) propionaldehyde,

2- (cyclohexylmethyl -2- 3-methylcyclopentylthio) -3- methylhexanal,

2-phenyl-2- cyclopentylmethylthio -8-nonenal,

2- 2-cyclooctenl-ylthio butyraldehyd e,

1,2-bis (formylmethylthio eth ane,

3 1,6-bis 1 -formylethylthio) -3 -methylhexane,1,18-'bis(l-ethyl-l-formylpropylthio) octadecane,1,3-bis(1-formyl-4-pentenylthio)cyclopentane,1,4-bis(phenylformylrnethylthio) -2-butene, 3 ,6-bis(cyclohexylformylmethylthio cyclohexene, l,4-bis(1-formyl-2-phenylethylthio) benzene, and 1,2-diphenyl- 1 ,2-bis(formylmethylthio ethane.

Examples of some a,a-bis (hydrocarbylthio)aldehydes that can be preparedby the method of this invention are his (methylthio) acetaldehyde,

bis ethylthio acetaldehyde,

ibis (n-butylthio) acetaldehyde,

bis phenylthio) acetaldehyde,

bis (benzylthio) acetaldehyde,

2,2-bis (isobutylthio) propionaldehyde,

2,2-bis (n-hexylthio )butyraldehyde,

2,2-bis 3 -ethyloctylthio) hexanal, 2,2-bis(1-butyldecylthio)decanal,

2,2-bis (n-octadecylthio) butyraldehyde, 2,2-bis(et hylthio )eicosanal,bis(cyclopentylthio) acetaldehyde,

bis (allylthio acetaldehyde,

bis (2-cycloheXen-1-ylthio acetaldehyde,

2,2-bis (p-tolylthio propionaldehyde,

2,2-bis (3-methylcyclopentylthio butyraldehyde, agar-bis (methylthiophenylacetaldehyde, u,a bis(ethylthio)cyclohexaneacetaldehyde, 2,2-bis(n-propylthio -4-pentenal,

a,a-bis (n-butylthio -2-cyclooctene- 1 -acetaldehyde, oc,0t-biS(ethylthio -o-tolylacetaldehyde,

2,2-bis (n-propylthio) -3 -phenylpropionaldehyde, andOC,OC-biS(thy1thlO) cyclopentanebutyraldehyde.

Generally, any thiol satisfying the above general description thereofcan be employed in this invention. Examples of such thiols are asfollows:

Methanethiol, ethanethiol, l-butanethiol, Z-butanethiol, 3-hexanethiol,l-dodecanethiol, l-octadecanethiol, benzenethiol, p-toluenethiol,u-toluenethiol, 2-propene-1-thiol, cyclohexanethiol, 3-methylcyclopentanethiol, cyclopentanemethanethiol,2-cyclooctene-1-thiol, 1,2-ethanethiol, 2- methyl-l,6-hexanedithiol,1,18-octadecanedithiol, 1,3-cyclopentanedithiol, 2-butene-1,4-dithiol,2-cyclohexene-l,4- dithiol, p-benzenedithiol, and1,2-diphenyl-1,Z-ethanedithiol. The dithiols are not presently preferredto be employed in forming the -bis(hydrocarbylthio)aldehydes of thisinvention.

Also, any halo aldehyde satisfying the above description can be employedin this invention.

Examples of a-halo aldehydes are as follows: chloroacetaldehyde,'bromoacetaldehyde, 2-iodopropionaldehyde, 2 fiuorohexanal, 2chlorodecanal, 2 n octyl 2 bromodecanal, 2-chloroeicosanal,cyclopentylchloroacetaldehyde, 2-chloro-3-phenylpropionaldehyde,2-(2-cyclohexen- 1 yl) 2 bromopropionalde'hyde,2-(cyclohexylmethyl)-2-fluoro-3-methylhexanal,2-phenyl-2-iodo-8-nonenal, 2-chlorobutyraldehyde,2-ethyl-2-bromobutyraldehyde, 2- chloro-S-hexenal,phenylbromoacetaldehyde, and cyclohexylbromoacetaldehyde.

Examples of a,a-dihalo aldehydes are as follows:

difluoroacetaldehyde,

dichloro acetaldehyde, dibromoacetaldehyde,

diiodoacetaldehyde, chlorobromoacetaldehyde, fluoroiodoacetaldehyde,Z-fluoro-2-chloropropionaldehyde, 2,2-dibromodecanal,

2,2-dichloroeicosanal, 2,2-dibromo-3-butenal,a-fluoro-a-bromocyclohexaneacetaldehyde, a,u-dichloro-3-cyclohexene-l-acetaldehyde, a,ot-dibromophenylacetaldehyde, anda,a-dichlorocyclop entanebutyraldehyde.

4 if desired, the dihalo aldehydes can be employed as the hydrates.

As stated above pyridine, quinoline, isoquinoline and/ or a lower alkylderivative thereof can be used as the solvent in this invention. Morespecifically, a solvent employed in this invention is at least onematerial selected from the group consisting of pyridine, quinoline,isoquinoline, and monoalkyl and polyalkyl derivatives of pyridine,quinoline and isoquinoline which contain not more than 6 carbon atoms inany one alkyl group and not more than a total of 12 carbon atoms in allthe alkyl groups in any one molecule. Mixtures of these solvents can beemployed and are within the scope of this invention. Generally any loweralkyl derivative satisfying the above description can be employed inthis invention. Examples of suitable derivatives of this type are2-picoline, 3-picoline, 4-picoline, 2,4- lutidine, 2,6-lutidine,4-ethylpyridine, quinaldine, lepidine, 3-methylisoquinoline,5-ethyl-2-picoline, 2-isobutylpyridine, 3-n-hexylpyridine,2,3,4-trimethylpyridine, 2,4,6-trin-butylpyridine, 4-ethylquinaldine,3-n-hexylquinaldine, 2- n pentyl 3 n hexyllepidine,3-isopropylisoquinoline, 3-methyl-4-n-butylisoquinoline, and1,3-di-n-hexylisoquinoline. Pyridine is the solvent of choice. Althoughthe concentration of solvent in the reaction mixture can vary over awide range since it need be present only in an amount sulficient to aidthe formation of the ot-formyl sulfides, the solvent will usuallyconstitute from about 15 weight percent to about weight percent of thereaction mixture, more often constituting from about 25 weight percentto about 75 weight percent of the reaction mixture. It should be notedhere that the above solvents appear to be unique in effecting thedesired reaction of this invention. Neutral solvents such as benzene,ethyl ether and water, and other basic solvents such as triethylamine,cause the reaction involved to take different courses, thereby leadingto products other than those produced by practicing this invention.

Although the reactants can be employed over a wide operable range ofratios, the mole ratio of monothiol or dithiol to a-halo aldehyde shouldbe such as to provide from 1 to 6 SH groups per molecule of the OL-halOaldehyde, preferably from 1 to 3 -SH groups per molecule of the a-haloaldehyde. The order of addition of reactants is not critical. Batch orcontinuous reaction techniques can be employed. The reaction time canvary from about 1 minute to about 24 hours, usually falling in the rangeof from about 5 minutes to about 5 hours, depending on the reactivity ofthe reactants and the temperature employed. The desired temperature alsodepends on the nature of the reactants, but will usually be in the rangeof from about 0 to about 150 0., preferably from about 20 to about 70 C.

Silimarly, the amounts of reactants used in preparing thea,ot-bis(hydrocarbylthio) aldehyde can vary over a wide operable rangeof ratios. However, generally, the mole ratio of thiol to a,ot-dihaloaldehyde should be from about 2:1 to about 8:1, preferably from about2:1 to about 4:1. The order of addition of reactants presently does notappear critical. Batch or continuous techniques can also be employed.The reaction time can vary from about 1 minute to about 24 hours,usually falling within the range of from about 5 minutes to about 6hours, depending in part on the reactivity of the reactants andtemperature being employed. The desired reaction temperature alsodepends on the nature of the reactants, but will generally be within therange of from about 0 to about 200 0, preferably from about 40 to aboutC.

Reaction pressures for each method of this invention should besufficient to maintain the reaction mixture substantially in the liquidphase, although high pressures can be employed if desired. Suchpressures can vary over a wide operable range depending upon the chosenreactant, solvent, and reaction temperature.

The a-forrnyl sulfides of this invention and in particular(n-butylt-hio)acetaldehyde can have utility as intermediates, e.g., theycan be used in forming pharmaceutical agents, agricultural chemicalssuch as insecticides, fungicides, herbicides and the like, and2-(benzylthio)-2- methylpropionaldehyde is an intermediate for formingpenicillamine; polymerization modifiers; oil soluble complexing agents,i.e. additives in hyrocarbons such as oil, kerosene, gasoline and thelike; and drilling fluid additives.

The a,a-bis(hydrocarbylthio) adlehydes of this invention andparticularly bis(n-butylthio)acetaldehyde have utility as additives forpetroleum fractions, intermediates in the manufacture of pharmaceuticalagents, in the production of agricultural chemicals such asinsecticides, fungicides, herbicides and the like, and in forming dyes.

Example I Anhydrous chloroacetaldehyde was prepared by ether extractionof a 40 percent aqueous solution of the aldehyde, followed by drying ofthe ether extract over anhydrous magnesium sulfate, filtration of thedrying agent, and distillation of most of the ether. The crude anhydrouschloroacetaldehyde was about 80 percent pure, as determined by gaschromatography, the other 20 percent being essentially ether; thismaterial was suitable for use without further purification.

To a stirred solution of 90 g. (1.0 mole) of l-but-anethiol in 250 ml.of pyridine was added 32.4 g. of the freshly prepared anhydrouschloroacetaldehyde containing about 25.9 g. (0.33 mole) of the desiredaldehyde. The solution, which contained 66.7 weight percent pyridine,was stirred at 35 to 40 C. for 4 hours, then cooled and diluted withthree parts of water. The organic layer was separated, the aqueous layerwas extracted twice with ether. The organic layers were combined anddried over anhydrous magnesium sulfate, the drying agent was filtered,and the filtrate was concentrated on a steam bath. Gas chromatographicanalysis of the concentrate on a 4.5 foot silicone column indicated theyield of (n-butylthio)acetaldehyde, identified subsequently, to be about69 percent. In addition, two higher boiling components appearing to ben-butyl disulfide and 1,2-bis(n-butylthio)ethylene were present inyields of about 2.0 and 1.0 percent, respectively. The concentrate wasthen flash distilled to remove solvent, and the distillate wasredistillecl to give a product of 99 percent purity, as determined bygas chromatography, boiling at 84 C./20 rnm., 11 1.4724. The infraredspectrum of this product was consistent with that to be expected for(n-butylthio)acetaldehyde (C H OS).

Analysis.-Calculated for C H OS: C, 54.5; H, 9.01; S, 242. Found: C,55.0; H, 9.0; S, 23.2; Cl, 0.62. This clearly shows(n-butylthio)acetaldehyde was produced.

In order to further confirm that the product of the method of thisexample was (n-butylthio)acetaldehyde, the product of the method of thisexample was reacted with 2,4-dinitrophenylhydrazine which, if theproduct of the method of this example was (n-butylthio)acetaldehyde,should yield the 2,4-dinitrophenylhydrazone (C H N O S) of(n-butylthio)acetaldehyde.

Analysis of the 2,4-dinitrophenylhydrazone.--Calculated for C H N O S:C, 46.2; H, 5.2; N, 18.0; S, 10.3. Found: C, 46.1; H, 5.2; N, 17.3; S,10.5.

Example II An experiment was carried out essentially by the method ofExample I except that triethylamine was substituted for th pyridine usedas solvent, and the order of addition of reaction materials wasreversed. To a stirred solution of 32.46 g. of the crude anhydrouschloroacetaldehyde, containing 25.9 g. (0.33 mole) of the aldehyde, in250 ml. of triethylamine was added 60 g. (0.63 mole) of l-butanethiol.Dark particles separated from the reaction mixture during the additionof the mercaptan. The mixture was stirred at about 35 to 40 C. for 4hours. A large amount of white solid precipitated, in an exothermicreaction, during the early portion of this time period. Upon terminationof the 4-hour period of stirring, the reaction mixture, which containeda large amount of solids, was cooled. Water was then added, whereuponmost of the solid material dissolved. The organic layer was separated,and the aqueous layer was extracted twice with ether. The organic layerswere combined and dried over anhydrous magnesium sulfate. After removalof the drying agent and solvent, an attempt to distill the productresulted in extensive decomposition, and no (n-butylthio)acetaldehydecould be isolated. Thus, triethylamine is unsatisfactory for use as asolvent in this invention.

Example III To 250 ml. of benzene were added 37.0 g. of crude anhydrouschloroacetaldehyde of 70 weight percent purity, prepared as in ExampleI, containing 25.9 g. (0.33 mole) of the aldehyde, and 90.0 g. (1.0mole) of l-butanethiol. The resulting mixture was stirred atapproximately 35 C. for 4 hours. After the reaction mixture was cooled,it was washed with aqueous potassium carbonate, then with water. Thewashed benzene solution was dried over anhydrous magnesium sulfate.After removal of the drying agent, the solvent was evaporated to give aresidue which was found by gas chromatographic analysis to contain 2.7g. of n-butyl disulfide, 28.3 g. of 1,2bis(n-butylthio)ethylene, 25.7 g.of 1,1,2-tris(n-butylthio)ethane, and only a trace of(n-butylthio)acetaldehyde. Thus, benzene is unsatisfactory for use as asolvent in the preparation of (n-butylthio)acetaldehyde.

Example IV Another experiment was carried out by the procedure used inExample III except that 250 ml. of ethyl ether instead of benzene wasused as the solvent. Gas chromatographic analysis of the product,carried out as in the preceding experiment, showed this productcontained 2.9 g. of n-butyl disulfide, 22.1 g. of 1,2-bis(n-butylthio)ethylene, 26.5 g. of 1,l,2-tris(n-butylthio)ethane, andonly a trace of (n-butylthio)acetaldehyde. Thus, ethyl ether isunsatisfactory for use as a solvent in the preparation of (n-butylthio)acetaldehyde.

Example V To 250 ml. of water was added 37.0 g. of crude anhydrouschloroacetaldehyde of 70 weight percent purity, prepared as in ExampleI, containing 25.9 g. (0.33 mole) of the aldehyde, and 90.0 g. (1.0mole) of l-butanethiol. The resulting mixture was stirred atapproximately 35 C. for 4 hours. After the reaction mixture was cooled,it was extracted with ether. The ether extract was then washed withaqueous potassium carbonate, then washed with water, and. finally driedover anhydrous magnesium sulfate. After removal of the drying agent, thesolvent was evaporated to give a residue which was found by gaschromatographic analysis to contain 0.7 g. of n-butyl disulfide, 11.3 g.of 1,2-bis(n-butylthio)ethylene, 43.5 g. of1,1,2-tris(n-butylthio)ethane, and only 1.9 g. of(n-butylthio)acetaldehyde. Therefore, water is unsatisfactory for use asa solvent in the preparation of (n-butylthio acetaldehyde.

Thus, it is clearly shown that only the solvents of this invention willproduce the results of this invention.

Example VI A stirred solution of 78 g. (0.69 mole) of dichloroacetaldehyde, 300 ml. of l-butanethiol, and 500 ml. of pyridine washeated at from 78 to 80 C. for about 4 hours. The reaction mixture wasthen cooled, and about 29.9 g. of solid was removed by filtration. Thefiltrate (767 g.) was concentrated to 203 g. by heating and anadditional 23 g. of solid was removed by filtering. The filtrate wasthen concentrated to 127 g. by further heating. From this concentrateabout 70 g. of a distillate fraction was obtained by flash distillationwhich fraction was found by gas chromatographic analysis, withsubsequent identification of the major components, to contain 14.7 g. ofn-butyl disulfide, 49.2 g. (32.4 mole percent yield) of bis(n-butylthio)acetaldehyde, i.e., (n-C H S) CHCHO, and 6.1 g. ofunidentified residue. The n-butyl disulfide was identified by comparisonof its gas chromatographic retention time with that of an authenticspecimen of n-butyl disulfide. To identify thebis(n-butylthio)acetaldehyde, a new compound, a flash distilled productobtained above was redistilled whereby there was obtained a pure productdistilling at 96 to 98 C./0.05 millimeter, n 1.5045, which pure producthad the same gas chromatographic retention time as the componentdesignated above as his (n-butylthio acetaldehyde.

Elemental analysis and molecular weight determination of the productdistilling at 96 to 98 C./ 0.05 millimeter gave values in substantialagreement with those calculated for bis(n-butylthio)acetaldehyde (C H OSAnalysis.-Calculated for C H OS C, 54.5; H, 9.1; S, 29.1; molecularweight, 220.4. Found: C, 54.5; H, 9.1; S, 29.5; molecular weight, 207.Thus, it is shown that bis (n-butylthio)acetaldehyde was produced.

In order to further confirm that the product of the method of thisexample was bis(n-butylthio)acetaldehyde, it Was reacted with2,4-dinitrophenylhydrazine. This should yield the2,4-dinitrophenylhydrazone derivative melting point 61 to 62 C., ofbis(n-butylthio)acetaldehyde.

Analysis.-Calculated for C H N O S C, 48.0; H, 6.0; S, 16.0. Found: C,48.1; H, 6.4; S, 16.0.

Example VII A stirred mixture of 78 g. (0.69 mole) ofdichloroacetaldehyde, 250 g. of l-butanethiol, and 500 ml. of benzenewas heated at 80 C. for 4 hours. The reaction mixture was thenconcentrated on a steam bath. Gas chromatographic analysis of theconcentrated mixture showed that butyl (n-butylthio)thiolacetate,n-butyl disulfide, and the di-n-butyl mercaptal of(n-butylthio)acetaldehyde were produced in yields of 41.8 g., 12.7 g.,and 4.3 g., respectively. The identity of all three products wasdetermined gas chromatographically by comparison with authentic samples.No bis(n-butylthio)acetaldehyde was obtained. Thus, benzene wasunsatisfactory as a solvent in this reaction.

Example VIII A stirred mixture of 39 g. (0.346 mole) ofdichloroacetaldehyde, 130 g. of l-butanethiol, and 300 ml. of benzenewas heated at 210 F. for 4 hours. n-Butyl (butylthio)thiolacetate andn-butyl disulfide were produced in yields of 15.4 g. and 34.0 g.,respectively, as determined by gas chromatographic analysis of thereaction mixture following filtration and concentration. Nobis(n-butylthio) acetaldehyde was obtained. Thus, even at elevatedtemperatures benzene was unsatisfactory as a solvent in this reaction.

Example IX A mixtut: of 42 g. (0.28 mole) of trichloroacetaldehyde, 155ml. (1.40 moles) of l-butanethiol, and 300 ml. of pyridine was heated at70 C. for 4 hours. From the reaction mixture was obtained a 95 molepercent yield of the simple adduct, trichloroacetaldehyde n-butylhemimercaptal. When the same starting materials, in the same amounts,were heated at 210 C. for 4 hours, there were obtained a 19.8 molepercent yield of 1,2-bis(n-butylthio) ethane, a mole percent yield ofn-butyl disulfide, and a 7 mole percent yield of(n-butylthio)acetaldehyde di-nbutyl mercaptal. The identification of thetrichloroacetaldehyde n-butyl hemimercaptal was made by elementalanalysis and by comparison of its melting point with that of the knowncompound; the identification of the other products was made by gaschromatographic analysis. Thus, it was shown that trihaloacetaldehydesdo not undergo direct replacement of halogen, with the aldehyde groupCir remaining intact, as do the a-halo aldehydes, and (Lot-dihaloaldehydes of this invention.

Reasonable variations and modifications of this invention can be made,or followed in view of the foregoing disclosure and discussion, withoutdeparting from the spirit or scope thereof.

I claim:

1. A method of preparing an u-formyl sulfide comprising reacting anu-halo aldehyde of the formula with a thiol of the formula RSH where Ris a monovalent hydrocarbon radical selected from the group consistingof alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl and combinationsthereof; each R' is independently selected from the group consisting ofR and hydrogen; X is a halogen selected from the group consisting offluorine, chlorine, bromine and iodine; the number of carbon atoms in Rdoes not exceed 18; and the total number of carbon atoms in the a-formylsulfide does not exceed 30, the reaction taking place in at least onesolvent selected from the group consisting of pyridine, quinoline,isoquinoline, monoalkyl and polyalkyl derivatives of at least one ofpyridine, quinoline and isoquinoline containing not more than 6 carbonatoms in any one alkyl groups and not more than a total of 12 carbonatoms in all the alkyl groups in any one molecule.

2. The method of claim 1 wherein the halo aldehyde ischloroacetaldehyde, said thiol is butanethiol, said solvent is pyridine,and the oc-fOIHIYl sulfide is (n-butylthio) acetaldehyde.

3. The method of claim 1 wherein the temperature of carbon atoms in anyone alkyl group and not more than monothiol to 06-11810 aldehyde is inthe range of from about 1 to about 6 SH groups per molecule of the oc-halo aldehyde, and the solvent constitutes from about 15 to about percentof the reaction mixture.

4. A method of preparing an a-formyl sulfide comprising reaction ana-halo aldehyde of the formula with a dithiol of the formula HSYSH whereR is a monovalent hydrocarbon radical selected from the group consistingof alkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl and combinationsthereof; each R is independently selected from the group consisting of Rand hydrogen; X is a halogen selectedtrom the group consisting offluorine, chlorine, bromine and iodine; Y is a divalent hydrocarbonradical selected from the group consisting of alkylene, cycloalkylene,alkenylene, cycloalkenylene, arylene and combinations thereof; thenumber of carbon atoms in R or in Y does not exceed 18; and the totalnumber of carbon atoms in the ot-formyl sulfide does not exceed 30, thereaction taking place in at least one solvent selected from the groupconsisting of pyridine, quinoline, isoquinoline, monoalkyl and polyalkylderivatives of at least one of pyridine, quinoline and isoquinolinecontaining not more than 6 carbon atoms in any one alkyl group and notmore than a total of 12 carbon atoms in all the alkyl groups in any onemolecule.

5. The method of claim 4 wherein the temperature of reaction is fromabout 0 to about C. and the mole ratio of dithiol to a-halo aldehyde isin the range of from about 1 to about 6 SH groups per molecule of thea-halo aldehyde, and the solvent constitutes from about 15 to about 85weight percent of the reaction mixture.

6. A method of preparing an a,ot-bis(hydrocarbylthio) aldehydecomprising reacting an a, x-dihalo aldehyde of the formula with a thiolof the formula RSH where R is a monovalent hydrocarbon radical selectedfrom the group consisting of alkyl, cycloalkyl, alkenyl, cycloalkenyl,aryl and combinations thereof; R is independently selected from thegroup consisting of fluorine, chlorine, bromine and iodine; the numberof carbon atoms in R does not exceed 18; and the total number of carbonatoms in the a,a-bis(hydrocarbylthio)aldehyde does not exceed 40, thereaction taking place in at least one solvent selected from the groupconsisting of pyridine, quinoline, isoquinoline, monoalkyl and polyalkylderivatives of pyridine, quinoline and isoquinoline containing not morethan 6 carbon atoms in any one alkyl group and not more than a total of12 carbon atoms in all the alkyl groups in one molecule.

7. A method according to claim 6 wherein the dihalo References CitedFOREIGN PATENTS 150,502 1/1963 Russia.

LEON ZITVER, Primary Examiner.

R. H. LILES, Assistant Examiner.

US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,419,617 December 31 1968 Richard C. Doss It is certified that error appearsin the above identified patent and that said Letters Patent are herebycorrected as shown below:

Column 8, line 37, "carbon atoms in any one alkyl group and not morethan" should read reaction is from about 0 to 150 C. the mole ratio ofSigned and sealed this 7th day of April 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer WILLIAM E. SCHUYLER, JR.

